Endoscopic procedures provide a desirable, minimally invasive alternative to surgery in treating various internal ailments of the human body. Endoscopes comprise a long cylindrical tube having several channels or lumens, and can be inserted through a natural body lumen to an internal treatment site. Various procedures can be conducted by navigating instruments through the working channels of the endoscope. Frequently, viewing capability is provided through one of the channels of the endoscope to aid in conducting the procedure. Attachment of various accessory tools to the distal end of the endoscope that are remotely operable through a working channel of the endoscope and/or elements that track along the outside of the endoscope to the treatment site can broaden the range of procedures viable for endoscopic techniques. Accessory attachments for endoscopes are currently available to perform band ligation, mucosectomy and for endoscopic suturing and suture knot advancement. Such accessory devices must be securely attached to the distal end of the endoscope to prevent accidental release of the accessory in the patient potentially causing serious complications.
Presently available means for attaching such accessories to the distal end of an endoscope utilize a friction fit or set screws that are cumbersome for a physician to operate. Friction fit endoscopic attachment mechanisms comprise a cylindrical ring at the proximal end of the accessory device sized to fit tightly around the distal end of the endoscope. The close sizing and proper material selection provide frictional contact to hold the accessory onto the distal end of the endoscope. However, the close fitting high frictional engagement provided by the cylindrical attachment mechanism make loading the accessory onto the distal end of the endoscope cumbersome and time consuming. Additionally, the closely sized cylindrical component matches only one endoscope size and, therefore, different sizes of attachment mechanisms must be produced and kept on hand if different sized endoscopes are expected to be used.
Another type of attachment mechanism uses set screws threaded through an endoscopic accessory which push a movable shoe into tight engagement with the outside surface of the endoscope while another portion of the accessory device extends partially into the working channel of the endoscope to provide leverage against advancement of the set screw. Such an attachment mechanism has been used to secure an endoscopic suturing capsule as disclosed in U.S. Pat. Nos. 4,841,888, 5,037,021, 5,080,663, 5,792,153, all of which are incorporated herein by reference in their entirety. Although the movable shoe secured by the set screws provides a secure engagement for a range of endoscope sizes, it is cumbersome and time consuming for the physician to tighten the set screws to secure the device prior to the procedure.
It would be desirable to provide an endoscopic accessory attachment mechanism that securely attaches the accessory to the distal end of an endoscope and that can be applied easily and rapidly. It is an object of the present invention to provide such a mechanism and associated methods for its use.
It is noted that in the description of the present invention, “distal” refers to the direction along the device pathway leading internally to the patient and “proximal refers to the direction leading externally from the patient.